Operon bacterial gene clusters

Bacterial gene clusters are organized into a suprafunctional unit, the operon. Throughout this review the term operon is used in accord with the definition proposed by Ames and Martin [8] ... 

Bacterial genes are organized in clusters under common regulation. These clusters are called operons and are controlled by regulatory elements (Figure 26.2). 

In E. coli, about half the genes are clustered into oper-ons each of which encodes enzymes involved in a particular metabolic pathway or proteins that interact to form one multisubunit protein. For instance, the trp operon mentioned earlier encodes five enzymes needed in the biosynthesis of tryptophan (see Figure 4-12). Similarly, the lac operon encodes three enzymes required for the metabolism of lactose, a sugar present in milk. Since a bacterial operon is tran-... 

The cluster of genes that form a bacterial operon comprises a single transcription unit, which Is transcribed from a particular promoter Into a single primary transcript. In other words, genes and transcription units often are distinguish-... 

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